So no dice with din-usb adapter cable? I use one with my micro korg to control soft synths on pc and ios. And it works great. Do arduino and teensyboy require a daw? I thought they could pair with midi keyboard as standalone synth.

The Teensyboy code is aimed specifically at USB MIDI, not using DIN MIDI jacks. You need to use a computer and a DAW (such as Ableton Live or Logic) with it. An Arduinoboy, based on the Arduino series of microprocessors, is what you need for DIN MIDI such as what the MIcrokorg offers.

Got it to compile with some help from the pjrc forum, now it is blinking correctly for startup. However, the switch doesn't seem to be working, and each time I plug it in it settles on a different mode led at random. Haven't been able to get any sounds out, and I'm really only looking to use it for mGB.
Am I right in assuming it requires a powered midi keyboard? Has anyone got it working with a microkorg as the controller? Anyone else face this situation?

being the first time I copied and pasted it, I noticed the "verbose" option, so here is the entirety with that box checked:

 Arduino: 1.0.6 + Td: 1.22 (Windows XP), Board: "Teensy 2.0"
C:\Program Files (x86)\Arduino\hardware\tools\avr\bin\avr-g++ -c -g -Os -Wall -fno-exceptions -ffunction-sections -fdata-sections -mmcu=atmega32u4 -DF_CPU=16000000L -MMD -DUSB_VID=null -DUSB_PID=null -DARDUINO=106 -DTEENSYDUINO=122 -felide-constructors -std=c++0x -DUSB_MIDI -DLAYOUT_US_ENGLISH -IC:\Program Files (x86)\Arduino\hardware\teensy\cores\teensy -IC:\Program Files (x86)\Arduino\libraries\MIDI -IC:\Program Files (x86)\Arduino\libraries\EEPROM C:\Users\Joseph\AppData\Local\Temp\build3689661298163637741.tmp\Arduinoboy1_2_3_teensy.cpp -o C:\Users\Joseph\AppData\Local\Temp\build3689661298163637741.tmp\Arduinoboy1_2_3_teensy.cpp.o 

Led_Functions_teensy.ino: In function 'void updateBlinkLight(int)':
Led_Functions_teensy.ino:97: warning: comparison between signed and unsigned integer expressions
Led_Functions_teensy.ino: In function 'void updateStatusLight()':
Led_Functions_teensy.ino:109: warning: comparison between signed and unsigned integer expressions
Mode_LSDJ_SlaveSync_teensy.ino: In function 'void RealTimeLSDJSlave(byte)':
Mode_LSDJ_SlaveSync_teensy.ino:46: warning: suggest parentheses around && within ||
Mode_MidiGb_teensy.ino: In function 'void modeMidiGb()':
Mode_MidiGb_teensy.ino:37: warning: unused variable 'sendByte'
C:\Program Files (x86)\Arduino\hardware\tools\avr\bin\avr-g++ -c -g -Os -Wall -fno-exceptions -ffunction-sections -fdata-sections -mmcu=atmega32u4 -DF_CPU=16000000L -MMD -DUSB_VID=null -DUSB_PID=null -DARDUINO=106 -DTEENSYDUINO=122 -felide-constructors -std=c++0x -DUSB_MIDI -DLAYOUT_US_ENGLISH -IC:\Program Files (x86)\Arduino\hardware\teensy\cores\teensy -IC:\Program Files (x86)\Arduino\libraries\MIDI -IC:\Program Files (x86)\Arduino\libraries\EEPROM -IC:\Program Files (x86)\Arduino\libraries\MIDI\utility C:\Program Files (x86)\Arduino\libraries\MIDI\MIDI.cpp -o C:\Users\Joseph\AppData\Local\Temp\build3689661298163637741.tmp\MIDI\MIDI.cpp.o 

In file included from C:\Program Files (x86)\Arduino\libraries\MIDI\MIDI.cpp:14:
C:\Program Files (x86)\Arduino\libraries\MIDI\/MIDI.h:76: error: expected identifier before numeric constant
C:\Program Files (x86)\Arduino\libraries\MIDI\/MIDI.h:76: error: expected `}' before numeric constant
C:\Program Files (x86)\Arduino\libraries\MIDI\/MIDI.h:76: error: expected unqualified-id before numeric constant
C:\Program Files (x86)\Arduino\libraries\MIDI\/MIDI.h:95: error: expected declaration before '}' token 

Also, I've never used this {code} trick before hopefully it embedded correctly, and is more helpful this way

sorry for not posting the error straight away, I was at work posting from my phone in frustration. here is the entirety of the error message:

  This report would have more information with
  "Show verbose output during compilation"
  enabled in File > Preferences.
Arduino: 1.0.6 + Td: 1.22 (Windows XP), Board: "Teensy 2.0"
In file included from C:\Program Files (x86)\Arduino\libraries\MIDI\MIDI.cpp:14:
C:\Program Files (x86)\Arduino\libraries\MIDI\/MIDI.h:76: error: expected identifier before numeric constant
C:\Program Files (x86)\Arduino\libraries\MIDI\/MIDI.h:76: error: expected `}' before numeric constant
C:\Program Files (x86)\Arduino\libraries\MIDI\/MIDI.h:76: error: expected unqualified-id before numeric constant
C:\Program Files (x86)\Arduino\libraries\MIDI\/MIDI.h:95: error: expected declaration before '}' token

I suggest first backing up the original usb_api.cpp and usp_api.h, then replacing/overwriting them with those supplied in Arduinoboy1_2_3_teensy _Rev_2_2.zip.

Also, post the specific error message.

I replaced the lib mod files as directed and have tried new and old  versions of the arguing ide on both xp and windows 7, all with teensyduino installed, but just can't get past the verifying of the code. I have the device selected and set to midi. I've tried Borge the first and second versions of the code.

Closest I've come is still giving an error that seems related to the lib modifications, but it only gets that far when I've replaced them.

I'm super new to arduino. Has anyone else run into this problem getting the code loaded? Am I supposed to add copies of the lib mods instead of overwriting them?